1. Field of the Invention
The present invention relates to a curtain airbag system, and more specifically to a curtain airbag system that deploys an airbag so as to cover an interior side face of a vehicle in the event of a side collision of the vehicle, to thereby protect vehicle occupants.
2. Description of the Related Art
A curtain airbag that is housed in a position folded along from a front pillar portion to a roof side rail portion of a vehicle has already been proposed. This curtain airbag is designed to protect vehicle occupants' heads. The airbag is deployed to cover an interior side face of a vehicle, including side windows, when a predetermined or greater side impact is applied to a side body of the vehicle in a side collision or the like.
A conventional airbag, however, is not fixed at its lower end portions, so that its reaction force against an applied load is poor, resulting in a failure in reliable suppression of the collision between occupants and the interior side face. It has also been impossible with a conventional airbag to completely eliminate the risk that occupants and the like are thrown out of the vehicle in the event that the vehicle turns over on its side or the like.
Given this factor, Unexamined Japanese Patent Publication No. 10-278723 discloses a curtain airbag system in which the front end portion of a curtain airbag is fixed to the front pillar portion of a vehicle, and the rear end portion to the rear of a roof side rail portion. According to this curtain airbag system, a tension line is formed on a line that links both the fixing points mentioned above. Moreover, by coupling the rear end of the lower end portion of the curtain airbag and the rear portion of the vehicle body with coupling means, such as a strap, there is formed another tension line at the lower end of the curtain airbag. The forming of such tension lines reinforces the reaction force of the curtain airbag.
In the technology disclosed in the above publication, however, tension exists only along the tension lines and not in the entire curtain airbag. This produces the problem that it is impossible to provide full protection of occupants if a force acting on the occupant toward the outside of the vehicle is great.